(Applicant's Abstract) Recent advances in imaging now provide us with an outstanding opportunity to improve our knowledge about the relationship between cellular function and physiology of the airspaces in patients with asthma. The primary mission of the Imaging Core is to correlate changes in airway structure, physiology, and pathology with function of the recruited cell. The imaging data gained from the human and animal studies will be correlated with physiologic and cellular data obtained in Projects I-V. Our specific aims are to; 1) evaluate the influence of eosinophils on airway physiology using hyperpolarized helium-3 (3He) MR imaging of lung ventilation in human and animal models of asthma, 2) determine the regional distribution of metabolically active eosinophils in human and animal models of asthma using 18FDG PET, and 3) co-register the metabolic and physiologic data from PET and MRI using anatomic information from high-resolution CT scanning of the lungs. Since many of the proposed techniques are new, CORE C will be responsible for developing and performing the proposed imaging methods.